1. Field of the Invention
The present invention relates to an exhaust gas recirculation system for an internal combustion engine. More particularly, the present invention relates to an exhaust gas recirculation system for an internal combustion engine having a catalytic converter provided in the exhaust passage.
2. Background Information
Exhaust gas recirculation systems configured to recirculate a portion of the exhaust gas from automobile engines and other internal combustion engines to the intake passage of the engine have been known for some time.
For example, the internal combustion engine disclosed in Japanese Laid-Open Patent Publication No. 2003-83050 is configured to recirculate exhaust gas from a portion of the exhaust pipe (exhaust passage) located downstream of the catalytic converter to the intake pipe (intake passage) using an EGR pipe (recirculation passage).
There are also automobile engines that are configured to recirculate exhaust gas from a portion of the exhaust passage located upstream of the catalytic converter to the intake passage.
By conducting exhaust gas recirculation and controlling a flow regulating valve installed in the recirculation passage, pump losses and cooling losses can be reduced and the ratio of specific heat can be increased. As a result, the fuel efficiency can be improved.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved exhaust gas recirculation system. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.